The aim of this study was to determine whether the combination of 5-azacytidine and methyl GAG could improve on the results of 5- azacytidine alone and whether administration of methyl GAG as a continuous IV infusion would reduce the incidence of serious toxicity previously reported with this drug. Eight patients were entered onto the study and only 1 patient achieved a partial remission. All patients treated with this regimen suffered definite and often (severe nonhematologic toxicity), in particular, mucosal toxicity. Because of the poor responses and severe toxicity encountered with this regimen, it is felt that this combination is not suitable for further studies.